Is there an official ruling about this issue? It's probably more funny or ridiculous than it is a serious issue, but I still can't believe this didn't get fixed in 2024.
The fundamental issue I see is: Why would you define 2 things (Darkness and Heavily Obscured) and then say "darkness is heavily obscured" - when doing so is nonsensical? (e.g. Light does not travel through a fog cloud and a dark alley the same way.) And to make matters worse, there are now 2 different definitions for heavily obscured in the 2024PHB.
Definition 1) PHB2024 Exploration : "A Heavily Obscured area—such as an area with Darkness, heavy fog, or dense foliage—is opaque. You have the Blinded condition (see the rules glossary) when trying to see something there. ...AND... Darkness. Darkness creates a Heavily Obscured area. Characters face Darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon, or in an area of magical Darkness."
Definition 2) PHB2024 & Free Rules Glossary: "Heavily Obscured. You have the Blinded condition while trying to see something in a Heavily Obscured space. See also “Blinded,” “Darkness,” and chapter 1 (“Exploration”)."
The first definition says that darkness, even natural nighttime darkness is OPAQUE. This suggests that if you hide in a dark alley, you won't be able to see someone walking by with a torch because the darkness you're in is opaque and can't be seen through. Also, no one could ever see the stars at night because you can't see through darkness - unless there's a Full Moon which apparently provides enough light for you to see the stars?!?!? (PHB2024: "A full moon might bathe the land in Dim Light.")
The second definition seems to make sense for the dark alley or stars, because it is only difficult to see something that is IN the heavily Obscured area. However, definition 2 suggests that Fog Cloud prevents people from seeing things in the cloud, but doesn't prevent people in the cloud from seeing out and that the fog doesn't block line of sight.
Some spells like Darkness specify that they are heavily obscured AND also that they can't be seen through, and others like Fog Cloud are heavily obscured but don't state that the area is opaque, when common sense says that fog should be opaque. This suggests that the authors don't have a clear vision on how this is supposed to work and that they apply the definitions inconsistently.
Obviously, the answer is "use common sense" for fog and normal darkness, but this falls short when we get to stranger magical effect and spells like Shadow of Moil, where the "common sense" approach starts to break down and the RAI is unclear. The reason we have rules is to clearly define the gray areas!
I suggest using Definition 2 for most darkness conditions and Definition 1 for areas that are heavily obscured (but some spells and effects might need to be edited to reflect this).
You can see light sources through "natural darkness", like seeing the stars at night, or a distant torch in an underground tunnel.
The spell darkness creates something different ("magical darkness"). It is completely devoid of light - no light can enter it, no light can leave it. Everything inside is black, and you are completely blind while inside it. You cannot look through it to see a torch on the other side.
Is there an official ruling about this issue? It's probably more funny or ridiculous than it is a serious issue, but I still can't believe this didn't get fixed in 2024.
The fundamental issue I see is: Why would you define 2 things (Darkness and Heavily Obscured) and then say "darkness is heavily obscured" - when doing so is nonsensical? (e.g. Light does not travel through a fog cloud and a dark alley the same way.) And to make matters worse, there are now 2 different definitions for heavily obscured in the 2024PHB.
Definition 1) PHB2024 Exploration : "A Heavily Obscured area—such as an area with Darkness, heavy fog, or dense foliage—is opaque. You have the Blinded condition (see the rules glossary) when trying to see something there. ...AND... Darkness. Darkness creates a Heavily Obscured area. Characters face Darkness outdoors at night (even most moonlit nights), within the confines of an unlit dungeon, or in an area of magical Darkness."
Definition 2) PHB2024 & Free Rules Glossary: "Heavily Obscured. You have the Blinded condition while trying to see something in a Heavily Obscured space. See also “Blinded,” “Darkness,” and chapter 1 (“Exploration”)."
The first definition says that darkness, even natural nighttime darkness is OPAQUE. This suggests that if you hide in a dark alley, you won't be able to see someone walking by with a torch because the darkness you're in is opaque and can't be seen through. Also, no one could ever see the stars at night because you can't see through darkness - unless there's a Full Moon which apparently provides enough light for you to see the stars?!?!? (PHB2024: "A full moon might bathe the land in Dim Light.")
The second definition seems to make sense for the dark alley or stars, because it is only difficult to see something that is IN the heavily Obscured area. However, definition 2 suggests that Fog Cloud prevents people from seeing things in the cloud, but doesn't prevent people in the cloud from seeing out and that the fog doesn't block line of sight.
Some spells like Darkness specify that they are heavily obscured AND also that they can't be seen through, and others like Fog Cloud are heavily obscured but don't state that the area is opaque, when common sense says that fog should be opaque. This suggests that the authors don't have a clear vision on how this is supposed to work and that they apply the definitions inconsistently.
Obviously, the answer is "use common sense" for fog and normal darkness, but this falls short when we get to stranger magical effect and spells like Shadow of Moil, where the "common sense" approach starts to break down and the RAI is unclear. The reason we have rules is to clearly define the gray areas!
I suggest using Definition 2 for most darkness conditions and Definition 1 for areas that are heavily obscured (but some spells and effects might need to be edited to reflect this).
You've already answered your own question.
You can see light sources through "natural darkness", like seeing the stars at night, or a distant torch in an underground tunnel.
The spell darkness creates something different ("magical darkness"). It is completely devoid of light - no light can enter it, no light can leave it. Everything inside is black, and you are completely blind while inside it. You cannot look through it to see a torch on the other side.
This may not be clear in RAW, but it is certainly RAI. https://19216811.cam/
No official ruling wether Heavily Obscured area from mundane Darkness behave differently than magical one.